The principal objective of this project is to develop the framework for the use of electrical stimulation to reduce spasticity in stroke and spinal cord injury using surface skin electrodes. The experiments are designed to optimize stimulus parameters, to identify the class of afferents responsible for reflex suppression, to map out the cutaneous stimulus sites inducing spasticity reduction of specific muscle groups, to explore hypothetical spinal mechanisms to account for observed spasticity reduction in response to electrical stimulation and study the feasibility of clinical treatment of spasticity with electrical stimulation. Spasticity reduction will be quantified at the elbow and ankle using measurements of the reflex response to constant velocity ramp stretches in hemiparetic stroke patients. Joint torque and electromyograms of the major muscles will be measured during constant velocity ramp flexions and extensions before during and after stimulation to assess the effects of various experimental protocols for individual subjects.